1. Field of the Invention
The present invention relates to a folding portable data processing apparatus such as a personal computer, and in particular, it relates to a data processing apparatus having a retracted portable position and a spread use position.
2. Description of the Related Art
Recently, with increasing improvements in data processing apparatuses, there is a demand to carry data processing apparatuses, such as personal computers and word processors, and for a person to be able to use the same anywhere. In particular, a demand is increasing for a data processing apparatus which is not only small in size, light in weight, and portable, but is also easy to operate and is inexpensive.
One conventionally known portable data processing apparatus is a so-called book-type which comprises two foldable portions, i.e., a base portion and a display housing portion. A display such as a liquid crystal display is arranged on the inner surface of the display housing portion, and a keyboard is arranged on the upper surface of the base portion. When the apparatus is used, the display housing portion is opened to reveal the display and the keyboard. Such a book-type structure is disclosed, for example, in U.S. Pat. No. 4,571,456.
The portable computer disclosed in this conventional device comprises a base portion, a display housing portion pivotally attached the base portion by a hinge means at an intermediate position between the front and the rear of the base portion; and a rear cover portion attached on the base behind the display housing portion to form an additional housing. The display housing portion is pivotable from a closed latched position on the base portion to an erect position for viewing the display. The hinge means for pivotally connecting the display housing portion to the base portion is located at the central region of the base portion between the opposite lateral sides of the base portion, and the display housing portion is opened upwardly and rather rearwardly to a rearwardly tilted position so that the display on the inner surface of the display housing portion can be seen by an operator and the keyboard arranged on the upper surface of the base portion is simultaneously revealed.
The conventional structural arrangement or a structural arrangement similar thereto is used in many currently sold portable data processing apparatuses, but this does not mean that it is without problems.
First, in the conventional apparatuses, it is necessary to arrange many wires to connect the printed circuit in the computer unit in the base portion to the display such as a liquid crystal display. In the conventional structure, the display housing portion is opened upwardly and rather rearwardly to a rearwardly tilted position, so that the rotating angle of the display housing portion relative to the base portion is approximately 170 degrees. Therefore, in order to avoid damaging the wires due to repeated bending and stretching motions occurring with the opening and closing action of the display housing portion, an axial cavity is provided in the interior of the inner pin member of the hinge means along the central longitudinal axis thereof, and the wiring is axially passed through the axial cavity in the inner pin member of the hinge means. Conventional covered multicore cables are used for the wiring, or alternatively, a flexible printed wiring board comprising a polyimide base sheet may be used for the wiring. This is described in the above described United States patent.
Considering an actual mass-production of portable data processing apparatuses at the factory, the conventional structure in which the wirings are passed through the axial cavity in the inner pin member of the hinge means includes a number of drawbacks. First, many wires must be extended from the printed circuit in the computer unit in the base portion to the display in the display housing portion, as described above, but the step of inserting many wires through the axial cavity in the inner pin member of the hinge means cannot be easily done by an automated manufacturing process and the efficiency of the assembly work of the apparatus is low. The efficiency is also low when flexible printed wiring boards are used because the flexible printed wiring boards must be carefully handled so that they are not folded.
Secondly, it is difficult to make the structure having the axial cavity in the inner pin member of the hinge means with sufficient strength. In many cases when the apparatuses are roughly handled in the field, the hollow pin member of the hinge means may be damaged. Further, even though the hinge means is not actually damaged, when the action of the hinge means is not smooth, a part of the flexible printed circuit board may be scratched in the axial cavity in the inner pin member of the hinge means and a crack may occur at a part of the wiring pattern of the flexible printed wiring board due to repeated opening and closing of the display housing portion. These problems results from the structural arrangement in which the display housing portion must be rotated relative to the base portion by 170 degrees.
Further, in operating the keyboard for inputting information, it is recognized as desirable to arrange the keyboard so that the rear of the keyboard, viewed by the operator, is higher than the front of the keyboard. However, in the book type structure, the upper surface of the keyboard is generally horizontal. In order set the keyboard so that the rear of the keyboard is higher than the front of the keyboard, it is necessary to attach legs to the rear of the base portion to raise the rear of the bottom surface of the base portion. It is possible in principle to tilt the keyboard to the front in this manner, but a drawback exists in this method when the keyboard is actually used. Since the legs are located below the bottom surface of the apparatus and usually cannot be seen, there may be a case where the apparatus may be moved carelessly by mistake, which may result in that the legs touching and spilling beverage containers on a desk, or the legs touching the corner of the desk and the legs themselves being damaged. In addition, the length of the legs is usually constant, and it is not possible, as an option, to change the tilt angle of the keyboard as desired.